A suspension of 7-benzenesulfonyl-4H-benzo[1,4]oxazin-3-one (0.09 g., 0.3 mmol), (2-chloro-ethyl)-dimethyl-amine hydrochloride (0.056 g., 0.39 mmol) and potassium carbonate (0.095 g., 0.69 mmol) in 0.7 mL ethyl acetate was refluxed for 1 hour. To the reaction mixture was added 0.75 mL water, and reflux was continued for 3 hours. 30 mL Ethyl acetate was added, and the reaction mixture was washed three times with 15 mL water, dried over magnesium sulfate and concentrated in vacuo. The residue was purifed by flash chromatography (0 to 5% methanol in dichloromethane) to afford 0.055 g (0.15 mmol, 50%) of 7-benzenesulfonyl-4-(2-dimethylamino-ethyl)-4H-benzo[1,4]oxazin-3-one. MS: 361 (M+H)+, mp: 232.9-235.3° C. (HCl salt).
